Since the nineteen sixties it is known, that the Earth’s mantle is depleted relative to CI chondrite in numerous elements as a result of accretion and core-mantle differentiation. However one potentially very important group of elements has received considerably less attention in this context; and these elements are the siderophile but volatile elements (SVEs). SVEs perhaps provide important information regarding the timing of volatile delivery to Earth. For SVEs especially the partitioning between metal melt and silicate melt (Dmetal/silicate) at core formation conditions is poorly constrained, never the less these elements are very important for most of the core formation models.
Thus, the aim of this subproject is to produce coherent sets of metal melt – silicate melt partition coefficients for Se, Te, Tl, Ag, As, Au, Cd, Bi, Pb, Sn, Cu, Ge, Zn, In and Ga. In this project, we will disentangle the respective effects of temperature, pressure, and fO2 from element partitioning processes using a systematic series of isothermal and isobaric experiments with a fO2 reasonable for the time of core formation. In addition, to investigate the effects of varying melt compositions, which may reflect the late stages of core formation on Earth, the Moon and potentially also on Mars.
We will additionally constrain how SVEs partition between metal melts and a crystalizing silicate melt. Overall, our experimental results will provide direct information about when volatile elements accreted and they will help us determine how much volatile-rich material was accreted during and after core formation.
Loroch, D., Klemme, S., Berndt, J., Rohrbach, A., 2018: Experimentally determined trace element partition coefficients between hibonite, melilite, spinel, and silicate melts. Data in Brief, Vol. 21, pp. 2447-2463. 10.1016/j.dib.2018.10.100